Thank you for asking.
As the minister said, a rejection can come about for many different reasons, including inadequate funds. We want to make sure that everyone who comes to Canada, whether temporarily or permanently, will be successful once they are here.
Students, since that's what your question is about, may have their application rejected because they are unable to demonstrate that they will be able to continue to pay for their education while living on their own once in Canada.
We want to make sure that they are really coming here to study and that they will be able to graduate without requiring social assistance from Canada, or from other sources that could make them vulnerable once they are here. So it's only natural for them to have to demonstrate that they have the financial capacity to pay their bills and live on their own.